1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 // UNSUPPORTED: c++03, c++11, c++14 11 // REQUIRES: c++experimental 12 13 // <experimental/memory> 14 15 // observer_ptr 16 // 17 // constexpr explicit operator bool() const noexcept; 18 19 #include <experimental/memory> 20 #include <type_traits> 21 #include <cassert> 22 23 template <class T, class Object = T> test_operator_bool()24constexpr void test_operator_bool() { 25 using Ptr = std::experimental::observer_ptr<T>; 26 Object obj; 27 28 { 29 Ptr const ptr(&obj); 30 bool b = static_cast<bool>(ptr); 31 assert(b); 32 33 static_assert(noexcept(static_cast<bool>(ptr))); 34 } 35 36 { 37 Ptr const ptr(nullptr); 38 bool b = static_cast<bool>(ptr); 39 assert(!b); 40 } 41 42 static_assert(!std::is_convertible<Ptr const, bool>::value); 43 static_assert(std::is_constructible<bool, Ptr const>::value); 44 } 45 46 struct Bar {}; 47 test()48constexpr bool test() { 49 test_operator_bool<Bar>(); 50 test_operator_bool<int>(); 51 test_operator_bool<void, int>(); 52 53 return true; 54 } 55 main(int,char **)56int main(int, char**) { 57 test(); 58 static_assert(test()); 59 60 return 0; 61 } 62